Semisoud plastic lubricant



Patented Oct. 13, 1936 UNITED STATES 2,057,473 SEMISOLID PLASTICLUBRICANT Eli F. Burch,

Laurel Springs, N. Cities Service Oil Company,

J., as signor to Philadelphia, Pa.,

a corporation of Pennsylvania No Drawing. Applic 3' Claims.

This invention relates to lubricating compounds, and more particularlyconcerns an improved form of semi-solid plastic lubricant of the generaltype described in my recently expired U. S. Letters ,v Patent No.1,238,101, patented August 28th, 1917.

The primary object of the present invention is to provide a semi-solidplastic lubricant which shall be an improvement on the lubricantdescribed in my aforementioned Patent No.

1,238,101; and which lubricant shall have a wider field of applicationin the lubrication of gears, shackle bolts, hydraulic machinerybearings, and as a blending agent for imparting to other lubricants suchas soda base greases, valuable characteristics including waterresistance and adhesive properties. The improvement which forms thesubject of the present invention developed from the discovery that byemploying about 1 to 5% by weight of drying or semi-drying oil such asfish oil or linseed oil in compounding the lubricant, I can produce alubricant of improved characteristics from a far wider range of basicingredients than were suitable for use in preparing the lubricant whichis described in my aforementioned Patent No. 1,238,101.

The general method of preparing the lubricant which forms the subject ofthe present invention does not differ markedly from that described in myaforementioned Patent No! 1,238,101. For example, I may take the heavyresidual oil remaining after distillation of asphalt base crudepetroleum such as produced in the South Texas field, without substantialcracking, and after sep- 5 aration of the light gasoline, kerosene andgas oil fractions; and admix with approximately 72% by weight of thisresidual oil about 25% by weight of No. 5 spindle oil or other lightparaffinic lubricating oil, and approximately 3% by weight of 0commercial fish oil. These oils are mixed in a still at a temperature ofapproximately 200 F. and thoroughly agitated by blowing air therethrcughwhile the temperature is raised to approximately 400 F. to 450 F. Theair blowin of the mixture is continued at the temperatures specified fora period of 65 to 80 hours. The blowing operation is continued underheat until the mixture is reduced to a suitable semi-solid or greaseconsistency, for example, about as thick 5 as hard Vaseline orcommercial lubricating grease. I have found that I can prepare thelubricant in the above manner from almost any naphthenic base petroleumresiduum, and that I also have a wide choice in proportioning theingredients.

55 Thus, I may employ 50 to 80 parts by weight of Serial No. 27,56

ation Jme 20, 1935,

the naphthenic base petroleum residuum, gether with 45 to 15 parts byweight of light paraffinic petroleum lubricant, and 1 to 5 parts byweight of a drying or semi-drying oil having an iodine value in therange 125 to 1'75.

The resultant lubricant possesses a high degree of plasticity and hasgreat afiinity for metallic surfaces, is very unctuous and is stable inmaintaining its consistency over a wide range of temperature. Thelubricant is also characterized by 10 having a low internal frictioncoefiicient as compared to greases such as are compounded from soap andlubricating oils. The product is nonfluid at ordinary temperatures whenleft to stand, and slowly fluid when stirred, setting up again as 15 anon-fluid when allowed to rest; thus the product is not adapted toviscosity measurements and is too fluid to be measured by thepenetrometer except when it is set up, which condition does not measurethe characteristics of the product which 20 impart its commercial valueI have found that the method which is described in my aforementionedPatent No. 1,238,- 101 is not applicable to the treatment of naphthenicbase petroleum residuums in general, whereas the improved process isbroadly applicable and produces a satisfactory plastic lubricant. Asuitable plastic lubricant prepared as described herein analyzed about18% asphaltene content, and about 40% asphaltic resins. The 30 productthus analyzed was found to contain '7-8% saponifiable material, althoughonly 3% saponifiable oil (fish oil) was used in its preparation. Thepetroleum residuum which was used in preparing the lubricant abovereferred to had an asphaltene content of about 0.2%, and an asphalticresin content of approximately 11%. Other suitable lubricants have beenprepared from this same oil having an asphaltene content of 10% to 20%,and an asphaltic resin content 40 in the range 35% to A microscopicexamination of the product shows the asphalt particles are smooth andregular in outline, whereas the asphalt particles in the petroleumresiduum are rough and irregular in outline. The fish oil or 45 itsoxidized product apparently acts as a protective colloid for the asphaltparticles, preventing their agglomeration, and increasing theirsolubility inthe oil-asphaltic resin matrix, so that the finishedlubricant appears to comprise a smooth uniform dispersion of asphalteneparticles in a mixture of mineral oil and asphaltic resins.

The invention having been thus described, what is claimed as new is:

1. A semi-solid plastic lubricant consisting essentially of a thoroughlyoxidized and homo- 45 to 15 parts by weight of spindle oil and aboutenized mixture 01' 50 to 80 parts by weight of 1 to 3 parts by wei ht 1'fi h oi naphthenic base petroleumresiduum, 45 to 15 3. The process ofpreparing a lubricant which parts by weight of light paraflinicpetroleum luconsists in mixing about 50 5 bricant, and about 1 to 5parts by weight of dryefficient as compared to soap grease.

2. A semi-solid plastic lubricant consisting essentially of a.thoroughly oxidized and homogenized mixture of to parts by weight of 15naphthenic base petroleum oil residuum, about

